OK, let's work through this together. We're starting with 902 and we're going to multiply it by 355, which means we add 902 to itself 355 times.
Step 1: 0 + 902 = 902
Step 2: 902 + 902 = 1804
Step 3: 1804 + 902 = 2706
Step 4: 2706 + 902 = 3608
Step 5: 3608 + 902 = 4510
Step 6: 4510 + 902 = 5412
Step 7: 5412 + 902 = 6314
Step 8: 6314 + 902 = 7216
Step 9: 7216 + 902 = 8118
Step 10: 8118 + 902 = 9020
Step 11: 9020 + 902 = 9922
Step 12: 9922 + 902 = 10824
Step 13: 10824 + 902 = 11726
Step 14: 11726 + 902 = 12628
Step 15: 12628 + 902 = 13530
Step 16: 13530 + 902 = 14432
Step 17: 14432 + 902 = 15334
Step 18: 15334 + 902 = 16236
Step 19: 16236 + 902 = 17138
Step 20: 17138 + 902 = 18040
Step 21: 18040 + 902 = 18942
Step 22: 18942 + 902 = 19844
Step 23: 19844 + 902 = 20746
Step 24: 20746 + 902 = 21648
Step 25: 21648 + 902 = 22550
Step 26: 22550 + 902 = 23452
Step 27: 23452 + 902 = 24354
Step 28: 24354 + 902 = 25256
Step 29: 25256 + 902 = 26158
Step 30: 26158 + 902 = 27060
Step 31: 27060 + 902 = 27962
Step 32: 27962 + 902 = 28864
Step 33: 28864 + 902 = 29766
Step 34: 29766 + 902 = 30668
Step 35: 30668 + 902 = 31570
Step 36: 31570 + 902 = 32472
Step 37: 32472 + 902 = 33374
Step 38: 33374 + 902 = 34276
Step 39: 34276 + 902 = 35178
Step 40: 35178 + 902 = 36080
Step 41: 36080 + 902 = 36982
Step 42: 36982 + 902 = 37884
Step 43: 37884 + 902 = 38786
Step 44: 38786 + 902 = 39688
Step 45: 39688 + 902 = 40590
Step 46: 40590 + 902 = 41492
Step 47: 41492 + 902 = 42394
Step 48: 42394 + 902 = 43296
Step 49: 43296 + 902 = 44198
Step 50: 44198 + 902 = 45100
Step 51: 45100 + 902 = 46002
Step 52: 46002 + 902 = 46904
Step 53: 46904 + 902 = 47806
Step 54: 47806 + 902 = 48708
Step 55: 48708 + 902 = 49610
Step 56: 49610 + 902 = 50512
Step 57: 50512 + 902 = 51414
Step 58: 51414 + 902 = 52316
Step 59: 52316 + 902 = 53218
Step 60: 53218 + 902 = 54120
Step 61: 54120 + 902 = 55022
Step 62: 55022 + 902 = 55924
Step 63: 55924 + 902 = 56826
Step 64: 56826 + 902 = 57728
Step 65: 57728 + 902 = 58630
Step 66: 58630 + 902 = 59532
Step 67: 59532 + 902 = 60434
Step 68: 60434 + 902 = 61336
Step 69: 61336 + 902 = 62238
Step 70: 62238 + 902 = 63140
Step 71: 63140 + 902 = 64042
Step 72: 64042 + 902 = 64944
Step 73: 64944 + 902 = 65846
Step 74: 65846 + 902 = 66748
Step 75: 66748 + 902 = 67650
Step 76: 67650 + 902 = 68552
Step 77: 68552 + 902 = 69454
Step 78: 69454 + 902 = 70356
Step 79: 70356 + 902 = 71258
Step 80: 71258 + 902 = 72160
Step 81: 72160 + 902 = 73062
Step 82: 73062 + 902 = 73964
Step 83: 73964 + 902 = 74866
Step 84: 74866 + 902 = 75768
Step 85: 75768 + 902 = 76670
Step 86: 76670 + 902 = 77572
Step 87: 77572 + 902 = 78474
Step 88: 78474 + 902 = 79376
Step 89: 79376 + 902 = 80278
Step 90: 80278 + 902 = 81180
Step 91: 81180 + 902 = 82082
Step 92: 82082 + 902 = 82984
Step 93: 82984 + 902 = 83886
Step 94: 83886 + 902 = 84788
Step 95: 84788 + 902 = 85690
Step 96: 85690 + 902 = 86592
Step 97: 86592 + 902 = 87494
Step 98: 87494 + 902 = 88396
Step 99: 88396 + 902 = 89298
Step 100: 89298 + 902 = 90200
Step 101: 90200 + 902 = 91102
Step 102: 91102 + 902 = 92004
Step 103: 92004 + 902 = 92906
Step 104: 92906 + 902 = 93808
Step 105: 93808 + 902 = 94710
Step 106: 94710 + 902 = 95612
Step 107: 95612 + 902 = 96514
Step 108: 96514 + 902 = 97416
Step 109: 97416 + 902 = 98318
Step 110: 98318 + 902 = 99220
Step 111: 99220 + 902 = 100122
Step 112: 100122 + 902 = 101024
Step 113: 101024 + 902 = 101926
Step 114: 101926 + 902 = 102828
Step 115: 102828 + 902 = 103730
Step 116: 103730 + 902 = 104632
Step 117: 104632 + 902 = 105534
Step 118: 105534 + 902 = 106436
Step 119: 106436 + 902 = 107338
Step 120: 107338 + 902 = 108240
Step 121: 108240 + 902 = 109142
Step 122: 109142 + 902 = 110044
Step 123: 110044 + 902 = 110946
Step 124: 110946 + 902 = 111848
Step 125: 111848 + 902 = 112750
Step 126: 112750 + 902 = 113652
Step 127: 113652 + 902 = 114554
Step 128: 114554 + 902 = 115456
Step 129: 115456 + 902 = 116358
Step 130: 116358 + 902 = 117260
Step 131: 117260 + 902 = 118162
Step 132: 118162 + 902 = 119064
Step 133: 119064 + 902 = 119966
Step 134: 119966 + 902 = 120868
Step 135: 120868 + 902 = 121770
Step 136: 121770 + 902 = 122672
Step 137: 122672 + 902 = 123574
Step 138: 123574 + 902 = 124476
Step 139: 124476 + 902 = 125378
Step 140: 125378 + 902 = 126280
Step 141: 126280 + 902 = 127182
Step 142: 127182 + 902 = 128084
Step 143: 128084 + 902 = 128986
Step 144: 128986 + 902 = 129888
Step 145: 129888 + 902 = 130790
Step 146: 130790 + 902 = 131692
Step 147: 131692 + 902 = 132594
Step 148: 132594 + 902 = 133496
Step 149: 133496 + 902 = 134398
Step 150: 134398 + 902 = 135300
Step 151: 135300 + 902 = 136202
Step 152: 136202 + 902 = 137104
Step 153: 137104 + 902 = 138006
Step 154: 138006 + 902 = 138908
Step 155: 138908 + 902 = 139810
Step 156: 139810 + 902 = 140712
Step 157: 140712 + 902 = 141614
Step 158: 141614 + 902 = 142516
Step 159: 142516 + 902 = 143418
Step 160: 143418 + 902 = 144320
Step 161: 144320 + 902 = 145222
Step 162: 145222 + 902 = 146124
Step 163: 146124 + 902 = 147026
Step 164: 147026 + 902 = 147928
Step 165: 147928 + 902 = 148830
Step 166: 148830 + 902 = 149732
Step 167: 149732 + 902 = 150634
Step 168: 150634 + 902 = 151536
Step 169: 151536 + 902 = 152438
Step 170: 152438 + 902 = 153340
Step 171: 153340 + 902 = 154242
Step 172: 154242 + 902 = 155144
Step 173: 155144 + 902 = 156046
Step 174: 156046 + 902 = 156948
Step 175: 156948 + 902 = 157850
Step 176: 157850 + 902 = 158752
Step 177: 158752 + 902 = 159654
Step 178: 159654 + 902 = 160556
Step 179: 160556 + 902 = 161458
Step 180: 161458 + 902 = 162360
Step 181: 162360 + 902 = 163262
Step 182: 163262 + 902 = 164164
Step 183: 164164 + 902 = 165066
Step 184: 165066 + 902 = 165968
Step 185: 165968 + 902 = 166870
Step 186: 166870 + 902 = 167772
Step 187: 167772 + 902 = 168674
Step 188: 168674 + 902 = 169576
Step 189: 169576 + 902 = 170478
Step 190: 170478 + 902 = 171380
Step 191: 171380 + 902 = 172282
Step 192: 172282 + 902 = 173184
Step 193: 173184 + 902 = 174086
Step 194: 174086 + 902 = 174988
Step 195: 174988 + 902 = 175890
Step 196: 175890 + 902 = 176792
Step 197: 176792 + 902 = 177694
Step 198: 177694 + 902 = 178596
Step 199: 178596 + 902 = 179498
Step 200: 179498 + 902 = 180400
Step 201: 180400 + 902 = 181302
Step 202: 181302 + 902 = 182204
Step 203: 182204 + 902 = 183106
Step 204: 183106 + 902 = 184008
Step 205: 184008 + 902 = 184910
Step 206: 184910 + 902 = 185812
Step 207: 185812 + 902 = 186714
Step 208: 186714 + 902 = 187616
Step 209: 187616 + 902 = 188518
Step 210: 188518 + 902 = 189420
Step 211: 189420 + 902 = 190322
Step 212: 190322 + 902 = 191224
Step 213: 191224 + 902 = 192126
Step 214: 192126 + 902 = 193028
Step 215: 193028 + 902 = 193930
Step 216: 193930 + 902 = 194832
Step 217: 194832 + 902 = 195734
Step 218: 195734 + 902 = 196636
Step 219: 196636 + 902 = 197538
Step 220: 197538 + 902 = 198440
Step 221: 198440 + 902 = 199342
Step 222: 199342 + 902 = 200244
Step 223: 200244 + 902 = 201146
Step 224: 201146 + 902 = 202048
Step 225: 202048 + 902 = 202950
Step 226: 202950 + 902 = 203852
Step 227: 203852 + 902 = 204754
Step 228: 204754 + 902 = 205656
Step 229: 205656 + 902 = 206558
Step 230: 206558 + 902 = 207460
Step 231: 207460 + 902 = 208362
Step 232: 208362 + 902 = 209264
Step 233: 209264 + 902 = 210166
Step 234: 210166 + 902 = 211068
Step 235: 211068 + 902 = 211970
Step 236: 211970 + 902 = 212872
Step 237: 212872 + 902 = 213774
Step 238: 213774 + 902 = 214676
Step 239: 214676 + 902 = 215578
Step 240: 215578 + 902 = 216480
Step 241: 216480 + 902 = 217382
Step 242: 217382 + 902 = 218284
Step 243: 218284 + 902 = 219186
Step 244: 219186 + 902 = 220088
Step 245: 220088 + 902 = 220990
Step 246: 220990 + 902 = 221892
Step 247: 221892 + 902 = 222794
Step 248: 222794 + 902 = 223696
Step 249: 223696 + 902 = 224598
Step 250: 224598 + 902 = 225500
Step 251: 225500 + 902 = 226402
Step 252: 226402 + 902 = 227304
Step 253: 227304 + 902 = 228206
Step 254: 228206 + 902 = 229108
Step 255: 229108 + 902 = 230010
Step 256: 230010 + 902 = 230912
Step 257: 230912 + 902 = 231814
Step 258: 231814 + 902 = 232716
Step 259: 232716 + 902 = 233618
Step 260: 233618 + 902 = 234520
Step 261: 234520 + 902 = 235422
Step 262: 235422 + 902 = 236324
Step 263: 236324 + 902 = 237226
Step 264: 237226 + 902 = 238128
Step 265: 238128 + 902 = 239030
Step 266: 239030 + 902 = 239932
Step 267: 239932 + 902 = 240834
Step 268: 240834 + 902 = 241736
Step 269: 241736 + 902 = 242638
Step 270: 242638 + 902 = 243540
Step 271: 243540 + 902 = 244442
Step 272: 244442 + 902 = 245344
Step 273: 245344 + 902 = 246246
Step 274: 246246 + 902 = 247148
Step 275: 247148 + 902 = 248050
Step 276: 248050 + 902 = 248952
Step 277: 248952 + 902 = 249854
Step 278: 249854 + 902 = 250756
Step 279: 250756 + 902 = 251658
Step 280: 251658 + 902 = 252560
Step 281: 252560 + 902 = 253462
Step 282: 253462 + 902 = 254364
Step 283: 254364 + 902 = 255266
Step 284: 255266 + 902 = 256168
Step 285: 256168 + 902 = 257070
Step 286: 257070 + 902 = 257972
Step 287: 257972 + 902 = 258874
Step 288: 258874 + 902 = 259776
Step 289: 259776 + 902 = 260678
Step 290: 260678 + 902 = 261580
Step 291: 261580 + 902 = 262482
Step 292: 262482 + 902 = 263384
Step 293: 263384 + 902 = 264286
Step 294: 264286 + 902 = 265188
Step 295: 265188 + 902 = 266090
Step 296: 266090 + 902 = 266992
Step 297: 266992 + 902 = 267894
Step 298: 267894 + 902 = 268796
Step 299: 268796 + 902 = 269698
Step 300: 269698 + 902 = 270600
Step 301: 270600 + 902 = 271502
Step 302: 271502 + 902 = 272404
Step 303: 272404 + 902 = 273306
Step 304: 273306 + 902 = 274208
Step 305: 274208 + 902 = 275110
Step 306: 275110 + 902 = 276012
Step 307: 276012 + 902 = 276914
Step 308: 276914 + 902 = 277816
Step 309: 277816 + 902 = 278718
Step 310: 278718 + 902 = 279620
Step 311: 279620 + 902 = 280522
Step 312: 280522 + 902 = 281424
Step 313: 281424 + 902 = 282326
Step 314: 282326 + 902 = 283228
Step 315: 283228 + 902 = 284130
Step 316: 284130 + 902 = 285032
Step 317: 285032 + 902 = 285934
Step 318: 285934 + 902 = 286836
Step 319: 286836 + 902 = 287738
Step 320: 287738 + 902 = 288640
Step 321: 288640 + 902 = 289542
Step 322: 289542 + 902 = 290444
Step 323: 290444 + 902 = 291346
Step 324: 291346 + 902 = 292248
Step 325: 292248 + 902 = 293150
Step 326: 293150 + 902 = 294052
Step 327: 294052 + 902 = 294954
Step 328: 294954 + 902 = 295856
Step 329: 295856 + 902 = 296758
Step 330: 296758 + 902 = 297660
Step 331: 297660 + 902 = 298562
Step 332: 298562 + 902 = 299464
Step 333: 299464 + 902 = 300366
Step 334: 300366 + 902 = 301268
Step 335: 301268 + 902 = 302170
Step 336: 302170 + 902 = 303072
Step 337: 303072 + 902 = 303974
Step 338: 303974 + 902 = 304876
Step 339: 304876 + 902 = 305778
Step 340: 305778 + 902 = 306680
Step 341: 306680 + 902 = 307582
Step 342: 307582 + 902 = 308484
Step 343: 308484 + 902 = 309386
Step 344: 309386 + 902 = 310288
Step 345: 310288 + 902 = 311190
Step 346: 311190 + 902 = 312092
Step 347: 312092 + 902 = 312994
Step 348: 312994 + 902 = 313896
Step 349: 313896 + 902 = 314798
Step 350: 314798 + 902 = 315700
Step 351: 315700 + 902 = 316602
Step 352: 316602 + 902 = 317504
Step 353: 317504 + 902 = 318406
Step 354: 318406 + 902 = 319308
Step 355: 319308 + 902 = 320210

So, 902*355 = 320210